1. Technical Field
The present disclosure relates to power supply circuits and, particularly, to a power supply circuit for an infrared cut removable filter.
2. Description of Related Art
Surveillance cameras usually employ an infrared cut removable (ICR) filter that is arranged in front of a charge coupled device (CCD). The ICR includes an infrared filter and an optical interference filter. During the daytime, the infrared filter is switched in front of the CCD to filter out the infrared, so as to obtain undistorted images. At night, the optical interference filter is switched in front of the CCD instead of the infrared filter to eliminate the interference of the visible light, so that clear images can be obtained.
There are basically three power supply modes of different ICR filters: continuous power supply, pulse power supply, and instantaneous power supply. When a surveillance camera utilizes an ICR filter of different power supply modes from the former one (in repair, for example), the surveillance camera usually has to employ a corresponding kind of power supply circuit to power the ICR filter, which means that the hardware compatibility between the power supply circuit and the ICR filter is low.
Therefore, it is desirable to provide a new power supply circuit for an ICR filter, which can overcome the above-mentioned limitations.